oj.uz

Submission #66407

# Submission time Handle Problem Language Result Execution time Memory
66407 2018-08-10T12:01:16 Z Vahan One-Way Streets (CEOI17_oneway) C++17
100 / 100
 492 ms 65052 KB 
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
int n,m,k,u[200000],fup[200000],tin[200000],timer;
vector<pair<int,int> > g[200000],br,tr[200000];
vector<pair<int,pair<int,int > > > cuc;
char pa[200000];
int sz[200000],par[2000000],uxx[200000],ux[200000],ind[200000],parent[200000][22],tiin[200000],tout[200000],pp[200000],h[200000];
void setcreate(int a)
{
    sz[a]=1;
    par[a]=a;
}
int findparent(int a)
{
    if(par[a]==a)
        return a;
    return par[a]=findparent(par[a]);
}
void setunion(int a,int b)
{
    a=findparent(a);
    b=findparent(b);
    if(a==b)
        return;
    if(sz[a]>=sz[b])
    {
        par[b]=a;
        sz[a]+=sz[b];
    }
    if(sz[b]>sz[a])
    {
        par[a]=b;
        sz[b]+=sz[a];
    }
}
void dfs(int v,int p)
{
    u[v]=1;
    fup[v]=tin[v]=timer++;
    for(int i=0;i<g[v].size();i++)
    {
        int to=g[v][i].first;
        int ham=g[v][i].second;
        if(to==v)
        {
            pa[ham]='B';
            continue;
        }
        if(p==to)
            continue;
        if(u[to]==1)
        {
            fup[v]=min(fup[v],tin[to]);
            pa[ham]='B';
            setunion(v,to);
        }
        else
        {
            dfs(to,v);
            fup[v]=min(fup[v],fup[to]);
            if(fup[to]>tin[v])
                br.push_back(make_pair(v,i));
            else
            {
                pa[ham]='B';
                setunion(v,to);
            }
        }
    }
}
void dfs1(int v,int p)
{
    tiin[v]=timer++;
    u[v]=1;
    parent[v][0]=p;
    for(int i=1;i<=20;i++)
            parent[v][i]=parent[parent[v][i-1]][i-1];
    for(int i=0;i<tr[v].size();i++)
    {
        int to=tr[v][i].first;
        int ham=tr[v][i].second;
        if(u[to]==1)
            continue;
        pp[to]=ham;
        h[to]=h[v]+1;
        dfs1(to,v);
    }
    tout[v]=timer++;
}

bool upper (int a, int b) {
	return tiin[a] <= tiin[b] && tout[a] >= tout[b];
}
int lca (int a, int b) {
	if (upper (a, b))  return a;
	if (upper (b, a))  return b;
	for (int i=20; i>=0; --i)
		if (! upper (parent[a][i], b))
			a = parent[a][i];
	return parent[a][0];
}
int main()
{
    cin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int a,b;
        cin>>a>>b;
        uxx[i]=a;
        g[a].push_back(make_pair(b,i));
        g[b].push_back(make_pair(a,i));
    }
    for(int i=1;i<=n;i++)
        setcreate(i);
    for(int i=1;i<=n;i++)
    {
        if(u[i]==0)
            dfs(i,0);
    }
    for(int i=1;i<=n;i++)
        ind[i]=findparent(i);
    for(int i=0;i<br.size();i++)
    {
        int a=br[i].first,b=g[a][br[i].second].first,ham=g[a][br[i].second].second;
        uxx[ham]=ind[uxx[ham]];
        tr[ind[a]].push_back(make_pair(ind[b],ham));
        tr[ind[b]].push_back(make_pair(ind[a],ham));
    }
    for(int i=1;i<=n;i++)
        u[ind[i]]=0;
    timer=0;
    for(int i=1;i<=n;i++)
    {
        if(u[ind[i]]==0)
            dfs1(ind[i],ind[i]);
    }
    cin>>k;
    for(int i=1;i<=k;i++)
    {
        int a,b;
        cin>>a>>b;
        a=ind[a];
        b=ind[b];
        if(a==b)
            continue;
        int c=lca(a,b);
        cuc.push_back(make_pair(h[c],make_pair(a,b)));
    }
    sort(cuc.begin(),cuc.end());
    for(int i=0;i<cuc.size();i++)
    {
        int a=cuc[i].second.first,b=cuc[i].second.second;
        int c=lca(a,b);
        int e=a;
        while(e!=c)
        {
            int ee=parent[e][0];
            if(pa[pp[e]]=='R' || pa[pp[e]]=='L')
                break;
            if(uxx[pp[e]]==e)
                pa[pp[e]]='R';
            else
                pa[pp[e]]='L';
            e=ee;
        }
        e=b;
        while(e!=c)
        {
            int ee=parent[e][0];
            if(pa[pp[e]]=='R' || pa[pp[e]]=='L')
                break;
            if(uxx[pp[e]]==e)
                pa[pp[e]]='L';
            else
                pa[pp[e]]='R';
            e=ee;
        }
    }
    for(int i=1;i<=m;i++)
    {
        if(pa[i]==0)
            pa[i]='B';
        cout<<pa[i];
    }
    return 0;
}
/*
5 6
1 2
1 2
4 3
2 3
1 3
5 1
2
4 5
1 3
*/

Compilation message

oneway.cpp: In function 'void dfs(int, int)':
oneway.cpp:42:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<g[v].size();i++)
                 ~^~~~~~~~~~~~
oneway.cpp: In function 'void dfs1(int, int)':
oneway.cpp:80:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<tr[v].size();i++)
                 ~^~~~~~~~~~~~~
oneway.cpp: In function 'int main()':
oneway.cpp:124:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<br.size();i++)
                 ~^~~~~~~~~~
oneway.cpp:152:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<cuc.size();i++)
                 ~^~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 9848 KB Output is correct
2 Correct 12 ms 9952 KB Output is correct
3 Correct 11 ms 10004 KB Output is correct
4 Correct 11 ms 10184 KB Output is correct
5 Correct 14 ms 10184 KB Output is correct
6 Correct 13 ms 10184 KB Output is correct
7 Correct 12 ms 10416 KB Output is correct
8 Correct 13 ms 10424 KB Output is correct
9 Correct 15 ms 10424 KB Output is correct
10 Correct 11 ms 10424 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 9848 KB Output is correct
2 Correct 12 ms 9952 KB Output is correct
3 Correct 11 ms 10004 KB Output is correct
4 Correct 11 ms 10184 KB Output is correct
5 Correct 14 ms 10184 KB Output is correct
6 Correct 13 ms 10184 KB Output is correct
7 Correct 12 ms 10416 KB Output is correct
8 Correct 13 ms 10424 KB Output is correct
9 Correct 15 ms 10424 KB Output is correct
10 Correct 11 ms 10424 KB Output is correct
11 Correct 127 ms 16544 KB Output is correct
12 Correct 146 ms 20464 KB Output is correct
13 Correct 151 ms 26448 KB Output is correct
14 Correct 172 ms 32340 KB Output is correct
15 Correct 184 ms 34996 KB Output is correct
16 Correct 242 ms 38448 KB Output is correct
17 Correct 293 ms 41268 KB Output is correct
18 Correct 264 ms 41268 KB Output is correct
19 Correct 247 ms 44860 KB Output is correct
20 Correct 131 ms 44860 KB Output is correct
21 Correct 128 ms 44860 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 9848 KB Output is correct
2 Correct 12 ms 9952 KB Output is correct
3 Correct 11 ms 10004 KB Output is correct
4 Correct 11 ms 10184 KB Output is correct
5 Correct 14 ms 10184 KB Output is correct
6 Correct 13 ms 10184 KB Output is correct
7 Correct 12 ms 10416 KB Output is correct
8 Correct 13 ms 10424 KB Output is correct
9 Correct 15 ms 10424 KB Output is correct
10 Correct 11 ms 10424 KB Output is correct
11 Correct 127 ms 16544 KB Output is correct
12 Correct 146 ms 20464 KB Output is correct
13 Correct 151 ms 26448 KB Output is correct
14 Correct 172 ms 32340 KB Output is correct
15 Correct 184 ms 34996 KB Output is correct
16 Correct 242 ms 38448 KB Output is correct
17 Correct 293 ms 41268 KB Output is correct
18 Correct 264 ms 41268 KB Output is correct
19 Correct 247 ms 44860 KB Output is correct
20 Correct 131 ms 44860 KB Output is correct
21 Correct 128 ms 44860 KB Output is correct
22 Correct 492 ms 50156 KB Output is correct
23 Correct 389 ms 50648 KB Output is correct
24 Correct 453 ms 53144 KB Output is correct
25 Correct 450 ms 60708 KB Output is correct
26 Correct 467 ms 60708 KB Output is correct
27 Correct 443 ms 60708 KB Output is correct
28 Correct 124 ms 60708 KB Output is correct
29 Correct 229 ms 60708 KB Output is correct
30 Correct 264 ms 60708 KB Output is correct
31 Correct 228 ms 60708 KB Output is correct
32 Correct 304 ms 65052 KB Output is correct